The invention is directed to a process for the production of guanidine hydrochloride.
It is known that in reacting dicyandiamide with ammonium chloride in the molten condition guanidine hydrochloride is formed (German Pat. No. 752750). Guanidine hydrochloride likewise is formed if dicyandiamide or cyanamide is heated with ammonium chloride at a temperature between 80.degree. and 200.degree. C. in a solvent consisting essentially of liquid ammonia (Hill U.S. Pat. No. 2,221,478). Also guanidine hydrochloride is produced by the reaction of cyanamide with ammonium chloride at a temperature of 120.degree. to 170.degree. C. in aqueous medium (German OS No. 1,593,472). A disadvantage of these processes is that the necessary starting materials, dicyandiamide or cyanamide must be obtained in several steps via calcium cyanamide from calcium carbide.
Besides it is known that in the action of cyanogen chloride on dimethylamine under pressure at a temperature of 130.degree. to 180.degree. C. in a water nonmiscible organic solvent 1,1,3,3-tetramethyl guanidine is formed (German Pat. No. 1,958,095). If it is attempted to react cyanogen chloride in a corresponding manner with ammonia to produce guanidine or guanidine hydrochloride there are not obtained satisfactory yields.